This invention relates to a normally open clutch assembly, and specifically to a normally open clutch assembly controllable to modify rotational speed required for actuation.
Typically a centrifugal clutch assembly includes at least one friction disk rotatable to drive an output shaft. Pressure plates move axially to clamp the friction disks in response to movement of a front plate. A centrifugal weight moves radially outward in response to rotation of the clutch assembly. Rollers of the centrifugal weights move up a ramped surface of the front plate to move the front plate axially. Axial movement of the front plate compress a clamp spring and forces engagement between the pressure plates and the friction disks.
Conventional centrifugal clutches begin actuation within a desired range of rotational speed. The rotational speed required for clutch actuation is substantially fixed and does not provide for adaptation to current vehicle operating conditions. In some instances it may be desirable to begin or maintain clutch engagement at slower speeds, such as when coasting or moving downhill. Further it may be desirable to begin engagement at higher engine speeds, or slip the clutch such as when moving or starting on a steep grade.
Accordingly, it is desirable to develop a centrifugal clutch assembly that is controllable to modify engagement and actuation at various rotational speeds.